Mobile networks communication continues to grow rapidly. The mobile data usage will continue skyrocketing. New data applications and services will require higher speed and more efficient. Large data bandwidth application continues to attract more consumers. New technologies are developed to meet the growth such as carrier aggregation (CA), which enables operators, vendors, content providers and the other mobile users to meet the increasing requirement for the data bandwidth. However, carrier aggregation assumes multiple RF chains for signal reception even for physically contiguous spectrum, which introduces long transition time to activate more carriers from one carrier for larger data bandwidth and decreases the efficiency of the data transmission.
In frequency bands above 3 GHz, there could be a block of physically continuous spectrum up to hundreds of MHz. The single carrier operation for such large continuous spectrum is more efficient in both the physical (PHY) control, with lower control signaling overhead, and PHY data, with higher trunking gains. It is, therefore, to configure the large contiguous spectrum for large data transmission instead of configuring multiple small spectrum resources. However, from the system level, not all the user equipment (UEs) require large channel bandwidth. Further, for each UE, not all applications require large channel bandwidth. Given that wideband operation requires higher power consumption, the use of the large spectrum resource for control signaling monitoring and low-data-rate services is not ideal for power saving and bandwidth efficiency.
In the 3GPP RAN1, 5G base station should be able to support UEs operating with single wideband carrier & UEs operating with intra-band carrier aggregation over the same contiguous spectrum simultaneously. It is also agreed that UE RF bandwidth adaptation is supported for single-carrier operation. How to support UEs operating with single wideband carrier and UEs operating with intra-band carrier aggregation over the same contiguous spectrum simultaneously requires new design.
Improvements and enhancements are required to facilitate 5G base station to support UEs operating with single wideband carrier & UEs operating with intra-band carrier aggregation over the same contiguous spectrum simultaneously and to facilitate UE RF bandwidth adaptation in single-carrier operation.